Can anyone offer a link to flight box dimensions and field position ?

There are no flight box dimensions for IMAC. While there are center and end maneuvers on the Aresti, where you stand can be considered center

Thank you !!!

So there is no in or out on the box since there isn't one like the full scale?

No, just have your caller inform the judges "Sequence start" (they are sitting a few feet behind you) and go for it. "Sequence complete" after drawing your line after the last figure, then climb back up calm your nerves and fly the sequence again for that round.

Jon

If you are referring to announcing the start or finish.. it is still common to say "In the box" and "out of the box"

if that is not what you are asking, let us know.